Questions tagged [transactions]

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If a user confirmed a booking or transaction on the database system, but it failed and it falls over to the replica, what if the transaction is lost?

This is an overall system design and DBMS question: If the user books a ticket or an item on a website, how do we solve the issue of confirming a ticket is sold to the user, but the main Database ...
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Lost Update Problem and Recoverability and Commits

Does lost update problem must have Read first? Can Lost-Update problem occur in: 1] Conflict Serializable 2] Strict Recoverable I'm totally confused about basic. R2(X) R1(X) W1(X) C1 W2(X) Does this ...
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How does 2PL protocol apply to schedule of multiple transactions?

If a schedule follows the two-phase locking protocol, does every transaction have to follow 2PL, or is it the case that all locks must appear all unlocks in the whole schedule? I am a little confused ...
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Does upgrading after all locks and before all unlocks violate 2PL?

2PL's rule says: Upgrading of lock (from S(a) to X (a)) is allowed in growing phase. But what if upgrading lies after the last lock and before the first unlock? Does it still count "in the ...